Thank you , The response was clear. I can see now that by the formula Atltiude difference x del Increment / 60 that when the Alt Dif = 60 deg as in this case LHA=0, then the 60s would cancle themsleves leaving the remaining Declination Increment. Are the N.A.O. tables worth knowing how to use? Is there advantages for one or the other as far as precison goes or ease of use?